Nearn, 44, of 4840 W. Diversey Ave., is on trial with his son, Willie Nearn Jr., 18, of the same address, and Ron Norton, 47, of 2751 W. 63d St. They are charged with criminal damage to property, conspiracy to commit criminal damage to property and conspiracy to commit theft.

The three men allegedly tried to con 82-year-old Rose Rolek into believing she had to pay $50,000 to fix a leaky toilet. Lang, a retired proofreader, testified that he fell victim to a similar scam.

He said he first called Central Heating in August, 1984, because something was wrong with the thermostat in his Northwest Side home. A man named Arthur LaGace, 39, of 3410 N. Paris Ave., responded to the call.

LaGace, who testified Thursday for the second time in the trial, described how he and his brother sabotaged Lang`s home and convinced him to pay for repairs.

LaGace, guaranteed probation in exchange for his testimony against his three former co-workers, testified last week that he had similarly conned Rolek.

``You`re the same guy who testified last week, the same guy with the six felony convictions, right?`` asked Clyde Lemons, Nearn Sr.`s lawyer.

``Right,`` answered LaGace, an ex-convict who still works in the home repair business.

``You were ripping people off last month, weren`t you?`` Lemon asked.

``Prior to last month, I probably did one or two jobs, yes,`` he answered.

LaGace admitted that he talked to Lang while his brother, William LaGace, 26, stuffed the toilet with tissues. The toilet overflowed, and Lang agreed to let them fix it.

After they left, though, ``I put my hands in the toilet and pulled out the Puffs they had stuffed in there,`` Lang said. He then canceled the repair, he said.

Undaunted, LaGace and his brother returned the next day. This time, LaGace distracted Lang while his brother went to the basement and stuffed the drain with plastic bags, LaGace said.

The toilet overflowed again, and this time Lang agreed to let them fix the pipes for $2,400. But while they were ``working`` on the pipes, they were stuffing them with clay, LaGace said. The basement flooded.

Norton, who allegedly was called in by LaGace, told Lang that ``it`s a bigger job than he thought and it would cost $56,000,`` Lang testified.

They finally agreed on $50,000 and Lang gave them $25,000 of it before he caught on to the scam, he said.

Last week, Rolek testified that seven men were arrested in her Bridgeport home on Sept. 10, 1984. She said they were digging up her basement after they tricked her into signing a $50,000 contract.